There's a secret achievement linked to it- you have to play the speedrunner route and get to the Hinterlands chapter.
You'll see an option that isn't there for the other playthroughs. You have to waste all 7 days going to the location (you'll get different text each time), and an achievement for finishing it. This unlocks the purple fur option starting with chapter 14 for all playthroughs.
And yes we did put that there to fuck with Eddio.